The advent of the wildlife rabies epidemic in the East has severely taxed law enforcement and animal control departments from Florida to New Hampshire. The problem has recently become such a concern that an "800" phone number has been established in at least one state to provide information to the public by answering questions on rabies related problems.
If a person is bitten by an animal and the animal is rabid, a post exposure vaccine must be given to avoid the fatal disease in humans. Since the treatment is expensive, painful and possibly life threatening to someone with other preexisting medical conditions, it is imperative that the animal suspected of carrying the virus be tested for the rabies virus. The brain of a potentially infected animal can be tested for the rabies virus if the animal is captured. Presently, the animals are frequently captured by shooting. Shooting, however, may be construed as an inhumane method of euthanizing animals and in many situations may endanger bystanders. Shooting, furthermore, can destroy the brain which is used for testing for infection with the rabies virus. Injection of the animals offers a more humane method of euthanizing the animal and provides a method of euthanizing which can be practiced without endangering bystanders.
There are several devices currently available for remotely injecting animals with solutions to inoculate, medicate or euthanize animals. The injection solutions will hereafter be referred to as drugs irrespective of their functions. These injection devices have been developed primarily for use by the veterinarian community. These injection devices are expensive, complex in design and can be cumbersome to load in the field. These limitations make the devices currently available ill-suited for use by the law enforcement officers or animal control officers who are responsible for capturing potentially rabid animals or for conservation officers who may wish to sedate an animal for observation.
One of the early remote animal injecting devices is described in U.S. Pat. No. 3,494,358 which discloses a design developed for veterinarians. The device uses a standard syringe held in place with multiple clips and has a complex triggering mechanism which must be cocked before the device is ready for service. The complexity of the device makes loading the device difficult. Furthermore, the complexity of the device makes it unreliable in field conditions where the injection device may be stored in hostile environments such as the back of an open truck. Additionally, the loading and removal of the syringe in the injection device is difficult.
More recent patents teach somewhat simpler injection devices. U.S. Pat. No. 3,780,734 has simplified the injection device, however, the syringe must be loaded in a canister before it can be used. Thus, a setup time is required before the device can be used. U.S. Pat. No. 3,840,007 teaches another injection device which suffers from a similar problem as that of the '734 patent since the syringe is loaded into a two-part canister.
U.S. Pat. No. 3,880,162 discloses a remote drug injection device having a syringe barrel which is placed in a metal sheath to provide stability and strength to the barrel. The standard plunger designed for the syringe barrel is replaced by a specially manufactured pole plunger, which is a pole having one end contoured to form a plunger. Since the syringe barrel is maintained in the metal sheath by friction, insertion and removal of the syringe can be difficult. If the metal sheath is too loose, it will not adequately grip the syringe while in use. If the sheath is too tight, it may be difficult to remove the syringe barrel and needle from the sheath. This becomes a particular concern when the animal the device has been used on is suspected of having an infectious disease and prolonged contact with the used syringe with the possibility of a needle puncture could endanger the person injecting the animal.
One of the injection devices which is currently available through Carl Jackson of Colebrook, N.H. is a device which employs many of the elements of the injection device of the '162 patent but eliminates the metal sheath by using the injection barrel and plunger such as taught in U.S. Pat. No. 3,209,695. The '695 patent discloses an injection projectile which can be fired at the animal. Once the needle penetrates the animal, a small explosive charge is detonated which actuates the plunger injecting the drug into the animal. Loading the drug injection device of the '695 patent is difficult since the appropriate dosage must be measured and poured into the barrel. In the injection device currently sold by Carl Jackson, the chamber of the '695 patent replaces the syringe of the '162 patent and the explosive charge of the '695 patent has been replaced by a plunger pole, similar to the pole taught by the '162 patent. The resulting device is difficult to load since the front cap with the needle attached to it has to be unscrewed and the drug poured into the barrel. Unscrewing the endcap can be particularly difficult in field conditions if dirt or corrosion gets into the threads.
Thus, there is a need for a simple injection device for remote drug injection of animals which can be quickly loaded with a syringe having a standard barrel and plunger. The injection device also needs to be sufficiently simple to avoid damage to its mechanism under the conditions of field use.